Alignment and support hydraulic jack



y 2, 1957 J. BRANDT ALIGNMENT AND SUPPORT HYDRAULIC JACK Filed March 16, 1966 4 mw Mo II M Q m 2 1 Q S .1 r w 1 g 8 w 2 f x w w. 3 f J I I Li INVENTOR. JOBST BRANDT ATTORNEY United States Patent 3,317,186 ALIGNMENT AND SUPPORT HYDRAULIC JACK Jobst Brandt, Menlo Park, Califi, assignor to the United States of America as represented by the United States Atomic Energy Commission Filed Mar. 16, 1966, Ser. No. 536,592 6 Claims. (Cl. 254-93) The invention relates to jacks, and more particularly to a jack which may be operated 'by means of hydraulic pressure to move a load object precisely to a selected position, and then be further operated to mechanically retain the object precisely in the selected position to permit removal of the hydraulic pressure.

In particular instances, it is necessary to lift or move an object precisely to a selected position in constrained quarters or at remote locations, and then necessary to maintain the object precisely in that position over long periods of time. Various types of hydraulic and mechanical jacks are well know in the art for so moving an object precisely to a selected position. In using a hydraulic jack, an object may be moved precisely to a selected position, but it is thereafter ditficult to maintain the object precisely in position due to the tendency of hydraulic systems to leak over long periods of sustained pressure. Moreover, hydraulic jacks, even in a leakproof fixed volume system, are subject to piston displacement caused by volumetric changes in the hydraulic fluid due to temperature changes. It is necessary, therefore, to continuously monitor and adjust a hydraulic jack when maintaining an object thereby in a selected position.

Mechanical jacks, on the other hand, e.g., screw and scissor jacks, may be used to lift an object precisely to a desired position and to maintain the object precisely in that position over a long period. However, a mechanical jack suitable for achieving such results with heavy loads is comparatively large and expensive, and it is difficult to apply the large driving forces required.

Generally, hydraulic jacks are very compact and inexpensive as compared to an equivalent mechanical jack, and the driving force is much more easily applied.

One method by which the advantages of both hydraulic and mechanical jacks may be obtained is to precisely position the object initially by means of a hydraulic jack and then to maintain the object in position by means of a mechanical jack. This method, however, requires that two jacks be used at each location at which an object is to be lifted, and therefore involves complex manipulation of two jacks, as Well as the expense of two jacks. Furthermore, in many locations there is not room enough for two jacks. The added expense of two jacks and their attendant manipulation becomes especially important at a large installation where, for example, a very long, somewhat flexible, heavy load object is to be positioned at many points, as for example, magnets and other components as used particularly in a two-mile linear accelerator.

It is an object of the invention to jack.

Another object is to provide a reliable, compact, inexpensive jack which maybe operated to precisely move an object to a selected position and maintain the object precisely in the selected position over an extended period.

Another object is to combine in a single jack the desirable features of both a hydraulic jack and a mechanical jack.

Another object is to move an object by means of hydraulic pressure to a selected position and then to maintain the object in the selected position by means which permit removal of the hydraulic pressure.

In brief, according to the invention, a jack is provided which comprises a main cylinder which also serves as a provide an improved base. The :base cylinder is fitted with a movable lift member or piston. Means are provided for applying hydrauling pressure to the piston to drive it against the object to be moved. The outer surface of the main cylinder includes screw threads formed therein. A fixed support means, in the form of a cylindrical sleeve, is concentrically mounted on the main cylinder and is formed with screw threads on its inner surface which mate with the threads on the outer surface of the main cylinder. The screw threads permit the support sleeve to be positioned precisely inward and outward coaxially with respect to the base cylinder.

A load may be precisely moved to a selected position by controlled application of hydraulic pressure to the piston. The piston is driven thereby against the object to precisely move the object to the selected position. To maintain the object in the selected position, means are provided for moving the support cylinder upward with respect to the main cylinder into engagement with the object. With the support cylinder against the object, the object is permanently held there-by in the selected position, thus eliminating the need to maintain a continuous hydraulic pressure against the piston.

To enable one skilled in the art to practice the invention more readily, an express embodiment thereof, given by way of example only, is described hereinafter with reference to the accompanying drawing in which the figure is a partial cross sectional View of a hydraulic jack, according to the invention.

More particularly, the embodiment of the invention shown in the figure is a jack 20 which includes a cylinder 22 that also serves as a support column as described below. Cylinder 22 includes an elongated tubular wall portion 23 of generally uniform circular configuration, closed at one end, providing a base 24 for mounting the jack on a firm foundation. The base cylinder 22 is provided with a piston 25, fitted for axial movement within said tubular portion 23 therein. The inner periphery of the upper end of the tubular cylinder portion 23 is cut away and formed with threads 26 for receiving a gland nut 27 which provides an upper sliding alignment bearing surface for the outer surface of piston 25, to accommodate heavy side thrust loads. The lower portion of the piston is formed at a position somewhat above the end, with an enlarged circumferential shoulder 28, and at the end therebelow with a reduced diameter circumferential groove 30. The enlarged shoulder 28 bears outwardlyin sliding alignment relation against the cylinder portion 23, while the reduced diameter shoulder 30 carries a piston ring 32, O-ring or other equivalent means disposed in a groove for sealing the gap between the piston and the wall of cylinder portion 23.

Hydraulic pressure may be applied to the piston 25 by means of a pump 34 which forces fluid from a reservoir 36 through a conduit 33 and a passage 49, formed in cylinder 'wall 23, into chamber 41 in the lower end of the base cylinder below piston 25 to bear thereagainst. The rate of flow of fluid to the cylinder chamber 41, and therefore the extent and the rate at which the piston 25 is moved upward, may be controlled by a valve 42 in the conduit. Passage 40 may be advantageously formed with a constricted diameter orifice to damp surge pressure or movement of piston 25. Downward movement of the piston may be controlled by means of -a valve 43, disposed in return conduit 44, to permit fluid to flow out of the cylinder back into reservoir 36.

Application of hydraulic pressure to lower end of the piston 25 causes the piston to move upward into engagement with an object 44.' The object may be elevated precisely to the selected position shown by manipulation of valves 42 and 43. With the object 44 in the selected position, the piston is in a raised position.

Patented May 2, 1967 A retractable load bearing support sleeve 46 is provided to mechanically maintain the object 44 in the selected position to permit removal of the hydraulic pressure. The support sleeve 46 is disposed concentrically about the upper portion of tubular cylinder portion 23,

- and is formed with screw threads extending from its lower inner surface for engagement with screw threads 48 formed on the outer surface of cylinder portion 23. The sleeve 46 is provided with radially outward open holes 49 for receiving the ends of bars 50 which may be manipulated for screwing the holding cylinder upward with respect to the main cylinder 22, or with the equivalent means well known in the art. After the object 44 is moved to the selected position, the sleeve 46 is screwed upward until an upper fiat terminal surface 52 thereon is in snug engagement with the object. Thereafter, upon release of the hydraulic pressure, the object is maintained in the selected position by the support sleeve 46 acting in cooperation with the base cylinder 22 to provide a rigid support column, thereby eliminating the need to operate the pump 34 or to maintain hydraulic pressure against the cylinder 25.

While one embodiment of the present invention has been shown and described, further embodiments or combinations of those described herein will be apparent to one skilled in the art without departing from the spirit of the invention or from the scope of the appended claims.

The invention claimed is:

1. A jack for moving an object to a selected position, and for maintaining the object in said position, compris- (a) a base support column means including a base for disposition in contact with a foundation;

(b) a movable load lift member mounted on said base for movement with respect thereto;

(c) means for moving said movable member upward from said base and against said object to move said object to said selected position;

(d) retractable positive support means mounted on said base; and

(e) means for moving said support means outward from said base into engagement with said object for holding said object in said selected position.

2. A jack according to claim 1 wherein said base support column defines a longitudinal cylindrical cavity surface, and said movable member is a piston in mating sliding sealed engagement with the wall surfaces defining said cylindrical cavity.

3. A jack according to claim 1 wherein said base column is a cylindrical column and includes an outer surface with threads formed thereon, and said support means is a generally cylindrical sleeve formed with internal threads in engagement with the threads on said outer surface.

4. A jack according to claim 1 wherein said means for moving said movable member includes means for applying hydraulic pressure against said movable member.

5. A jack according to claim 1 wherein said base column is cylindrical and has an outer surface with threads formed therein and defines a longitudinal cylindrical internal cavity; said movable member is a piston in mating engagement with the walls of said cylindrical cavity, and said support means is a cylindrical sleeve open at both ends, disposed concentric with said cylindrical base col umn, and with threads formed on its internal surface for engagement with the threads on the outer surface of the base column.

6. A jack according to claim 5 including means for applying hydraulic pressure to said piston for moving said piston against said object to move said object to said selected position, and means for extending said support means upward into positive support engagement with said object, thereby permitting removal of said hydraulic pressure from said piston, whereby said support means and said base are the sole support of said object in said selected position.

References Cited by the Examiner UNITED STATES PATENTS 2,214,440 9/1940 Rothery 254-93 2,227,460 1/1941 Morgensen 254-l 2,314,589 3/1943 Mandl 254-93 OTHELL M. SIMPSON, Primary Examiner. 

1. A JACK FOR MOVING AN OBJECT TO A SELECTED POSITION, AND FOR MAINTAINING THE OBJECT IN SAID POSITION, COMPRISING: (A) A BASE SUPPORT COLUMN MEANS INCLUDING A BASE FOR DISPOSITION IN CONTACT WITH A FOUNDATION; (B) A MOVABLE LOAD LIFT MEMBER MOUNTED ON SAID BASE FOR MOVEMENT WITH RESPECT THERETO; (C) MEANS FOR MOVING SAID MOVABLE MEMBER UPWARD FROM SAID BASE AND AGAINST SAID OBJECT TO MOVE SAID OBJECT TO SAID SELECTED POSITION; (D) RETRACTABLE POSITIVE SUPPORT MEANS MOUNTED ON SAID BASE; AND (E) MEANS FOR MOVING SAID SUPPORT MEANS OUTWARD FROM SAID BASE INTO ENGAGEMENT WITH SAID OBJECT FOR HOLDING SAID OBJECT IN SAID SELECTED POSITION. 